Impact of smoking habit on adult-onset Still's disease prognosis, findings from a multicentre observational study

The objective of this study is to describe the possible prognostic impact of smoking habit on adult-onset Still's disease (AOSD) patients, by the assessment of clinical characteristics, life-threatening complications occurrence, and mortality in smokers than non-smokers. A multicentre retrospective study of prospectively followed-up AOSD patients included in Gruppo Italiano di Ricerca in Reumatologia Clinica e Sperimentale (GIRRCS) cohort was conducted. Out of 185 AOSD assessed patients, 45 smokers were identified. These showed a higher frequency of pericarditis (35.5% vs 16.4%, p = 0.011), pleuritis (33.3% vs 14.3%, p = 0.008), and abdominal pain (17.7% vs 6.4%, p = 0.035). Furthermore, smokers showed higher values of systemic score (6.4 +/- 2.2 vs 5.4 +/- 1.8, p = 0.004), an increased rate of macrophage activation syndrome (MAS) (28.9% vs 6.4%, p < 0.0001) and of parenchymal lung disease (17.7% vs 12.6%, p = 0.035). Although not significant, these patients more frequently experienced a poor prognosis (13.3% vs 4.3%, p = 0.074). Smoking habit predicted MAS occurrence in both univariate (HR: 5.98, 95% CI: 2.45-14.57, p < 0.0001) and multivariate regression models (HR: 6.21, 95% CI: 2.46-15.70, p < 0.0001). Smokers had a significant higher risk of parenchymal lung disease in both univariate (HR: 3.97, 95% CI: 1.43-11.02, p = 0.008) and multivariate regression models (HR: 3.90, 95% CI: 1.36-11.23, p = 0.012). Smoking habit also increased the risk of mortality in univariate regression model (HR: 4.25, 95% CI: 1.33-13.55, p = 0.015). Smoking habit resulted to be a negative prognostic factor on AOSD patients. Smokers were characterised by a higher frequency of serositis and higher values of systemic score. Additionally, these patients were more frequently burdened by MAS and parenchymal lung disease associated with a poor prognosis.